Method of making electrical laminations



NWQ W, 19428 w. i RAY 7 METHOD OF MAKING ELECTRICAL LAMINATIONS FiledJan. 12, 194!) INVENTOR A TTURNE V Psiente Nov. 37. 384?;

MTE STATEg OFFWE METHOD OF ELIWTRICAL 2 Claims.

My present invention relates to laminations for the construction ofcores for transformers and other electrical apparatus.

Such laminations are usually punched from a long rolled band. oftransformer iron which, be cause of the method of its manufacture. has adefinite grain" wooing in the direction of its length. It has been foundthat, where such is present, the iron exhibits greater maimeticpermeability to the flux lines which are parallel to the direction of.the grain than to those which cross it.

t is, therefore, a main object of my invention to provide a method ofcutting iaminations from such a band so that, in the major portions ofthese laminations, the grain lies in substantially the same direction asthat of the path of the flux lines which pass through them when thecore, of which they form a part, is energizes.

Another object is the provision of o, method of cutting s shapedlaminations from such a band so that the arms oi the so are parallel tothe ob rection of the grain.

Another object is the provision of a method of cutting pairs of E and ishaped lsminations from a band of sheet metal so that none of thematerial is wasted.

Another object is the provision of a method of producing pairs of E andI-shaped iaminetions from a band of transformer iron having a longituciinal grain so that the path of the flux lines produced in a coreassembled from these parts will be substantially parallel. to the grainin the arms of the E-shapeo. lamination and. in the L shaped lamination.

Gther objects and. advantages of my invention be iouncl in thedescription, the drawing, and. the appended. claims.

For complete understanding of the invention, reference may be had to thefollowing detailed description and accompanying drawing, wherein:

figures i, 2, 3 and. i are, respectively, plan views of a strip oftransformer iron in the positions taken by it in the successive punchingoperations;

Figures 5 and 6 are plan views of the finished laminations; and

Figure 7 is a sectional view of a transformer assembled from thelamihatiohs and. taken in the plane of one of the pairs oflaioiiriations.

In the drawing. the numeral ii indicates a strip oi transformer ironhaving a longitudinal grain. Broken lines i2, i3 and i4 indicate thepositions which the enol of the strip takes prior to the successivepunching operations to be per formed on it to produce the laminations.

In Fig. 2, four holes l5 and it; have been punched in the strip. In Fig.3, two rectangular openings i. have been punched, the removetl (ill.

materiel fOllIlilg' two III-shaped laminations i8 shown Fig. 6. In Fig.4:, the strip has been out transversely in two places 42 and 2D to formtwo E-shape i laminations 2 1, shown in Fig. 5; a pressure peel:oreierably being arranged so as to support the end. lei-shaped portionas the doub1e-cut is mode.

The operations described in the precedin paragraph are preferablyperformed in an automatic punch press and occur simultaneously after thestrigo has progressed to the position shown in Fig. e. lit will be notedthat no material is wasted, other than that of the bolt holes 15 and InFig. 7, the broken lines indicate the grain arrangement of thelaminations, and lines 22 the general path oi the flux produced in thelamina tions by coil 23. lit will be noted that, other than in thevertical portion of the E-shaped lamination, the direction of the grainis substantially parallel to the path of the flux lines.

While I have described my present invention with reference to a.particular punching process, it is evident that modifications thereofare possible without departing from the spirit of my in vention. Forinstance, the width of the strip of metal employed may be two or moretimes the height of the E, a plurality of pairs of E-shaped portionsbeing out off in the final operation. I intend. therefore that myinvention be limited only by the scope of the appended claims.

I cleim as my invention:

l. The method of producing a plurality of pairs of E Li..lie.pe:ilamination; for an electrical core which consists in punchlin out from astrip of sheet metal, having a width equal to the height of said E, apair of I-shapeci portions from the parts of said strip corresponding;to the spaces between the adjoining arms of a pair of opposed iii-shapei portions arranged vertical to the axis of said strip, and thensevering said strip transversely across said spaces to form. said pairof i-shaped portions.

2. The method. of producing a plurality of pairs oi F. anti I-shap-ecilaminations for an electrical core which consists in punching out froma. band of lamination iron, having a longitudinal grain and a widthequal to the height of each of said E and ssici I, e. pair of I-shapedlaminations from the parts of an end portion of said band correspondingto the spaces between the adjoining arms of a pair of opposed Esl1apedlamination portions arranged at the end of and vertical to the axis ofsaid band, and then severing said bancl transversely in two places toform said pair of E-shapecl laminations, one of said severing placesbeing across said spaces.

Wm A. RAY.

